1. The Field of the Invention
The present invention generally relates to a cap that removably secures one device to another. In particular, embodiments relate to devices, systems and methods for pushing a drive shaft against a motor mount using a cap such that rotation of the motor mount causes rotation of the drive shaft while the cap is locked to the motor mount.
2. The Related Technology
Bioreactors are commonly used by the biopharmaceutical industry to grow cells and microorganisms. A typical bioreactor comprises a container in which the cells or microorganisms are contained. A mixing system is used to suspend and mix the components. For this purpose, an impeller is positioned in the container. A drive shaft extends from the impeller to a motor positioned outside of the container. The motor rotates the drive shaft which rotates the impeller. Examples of such systems are described in U.S. Pat. No. 7,682,067, issued Mar. 23, 2010.
In one embodiment, the drive shaft is removably secured to a motor mount which is rotated by the motor. A retention cap is used to secure the drive shaft to the motor mount. The retention cap and the motor mount are threaded so that the retention cap can be screwed onto the motor mount to be secured thereto. When secured to the motor mount, the retention cap causes the drive shaft to be secured to the motor mount so that the drive shaft rotates with the motor mount. By being secured to the motor mount, the retention cap also rotates therewith. A safety cap is positioned over the retention cap and secured to the body of the motor to make the system safer. Unlike the retention cap, the safety cap does not rotate with the motor mount.
To remove the drive shaft from the motor, the safety cap is first detached from the body of the motor and removed. The retention cap is then unscrewed from the motor mount and removed therefrom. The drive shaft can then be removed from the motor mount.
Although the above mixing system solves many problems of earlier mixing systems, it also has some problems of its own, especially with respect to the retention cap and the manner in which the drive shaft is secured to the motor. For example, if the threads on the retention cap and the motor mount are misaligned when the retention cap is screwed onto the motor mount, the threads can be damaged requiring replacement of the retention cap and/or the motor mount.
Furthermore, depending on the operator, different forces can be used each time the retention cap is screwed onto the motor mount. As such, it can be unclear how well the retention cap is secured to the motor mount. As noted above, the retention cap rotates with the motor mount when secured thereto. Rotation of the motor mount can cause vibrations to occur in the retention cap. If the cap is not properly tightened, these vibrations can potentially cause the cap to slowly unthread from the motor mount, thereby potentially hampering operation of the system.
In addition, a specifically designed wrench is used to secure retention cap to the motor mount. The required wrench adds cost to the system and can impede operation of the system if the wrench is lost or misplaced.
Accordingly, what is needed are mixing systems that solve one or more of the above problems. The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.